1. Field of the Invention
The present invention relates to a method of cleaning a deposition chamber and a deposition apparatus, and more particularly, to a method and an apparatus for cleaning metal oxides attached to elements inside of a deposition chamber.
2. Description of the Related Art
In the manufacture of semiconductor devices, a deposition process, for forming a film on a wafer, and a dry etching process are performed in a chamber maintained with high vacuum pressure. In the deposition process, deposition gases are provided into a deposition chamber with a wafer, and a film is formed on the wafer by a reaction between the deposition gases.
The film is desirably formed on a surface of the wafer for the deposition process. Reacting residues are, however, also substantially deposited on the inside of the deposition chamber including the other elements inside of the chamber. Also, reaction by-products that have not reacted with the wafer are partially attached on the inside and elements of the deposition chamber. When the thickness of the reacting residues or the reaction by-products attached in the deposition chamber becomes substantial, the reaction residues or by-products may separate from the inside and elements of the deposition chamber. As they separate from the inside and elements of the chamber, they may drop on the surface of a wafer and cause a fatal processing failure. To prevent this type of failure, a cleaning process should be performed periodically to remove the reaction residues by-products attached in the deposition chamber. The cleaning process is generally performed in situ without opening the deposition chamber or separating the deposition chamber from a deposition apparatus.
Recently, various thin films have been required for manufacturing a semiconductor device, thus leaving various kinds of reacting residues and reaction by-products. However, these residues and by-products generated during the formation of specific thin films may be hard to remove using a conventional process for in situ cleaning the deposition chamber. In fact, deposition processes for some specific thin films have been developed that lack an efficient process for in situ cleaning the deposition chamber where they are deposited. As a result, the deposition process for these specific films may not be able to be efficiently employed in a semiconductor manufacturing process. For example, an aluminum oxide (Al2O3) film is used as a dielectric film of a capacitor or a gate insulation film because the aluminum oxide film has a dielectric constant higher than that of a conventional silicon oxide film. However, reacting residues or reaction by-products are generated in its deposition process and are attached in the deposition chamber during the formation of the aluminum oxide film. The cleaning time for the deposition chamber may greatly increase because the reacting residues or the reaction by-products cannot efficiently be removed using conventional cleaning processes, because the etching rates of these residues and by-products are very low.
A method for cleaning a deposition chamber for an aluminum oxide film is disclosed in Japanese Patent Laid Open Publication No. 11-222679. According the Japanese Patent Laid Open Publication, a hydrogen fluoride (HF) gas is provided into the deposition chamber in order to remove aluminum oxides deposited in the deposition chamber. The HF gas is reacted with the aluminum oxide to generate solid-phased aluminum fluoride (AlF3) on a surface of the aluminum oxide. However, when the solid-phased aluminum fluoride is formed on the surface of the aluminum oxide, the deposition chamber may not be efficiently cleaned because aluminum oxide film beneath the aluminum fluoride cannot easily removed with a dry etching process.